Reinforced tow handle

ABSTRACT

An improved gripping handle for a tow line which includes an elongated, generally rigid core member having a layer of glass cloth disposed about and bonded to the outer surface of the core, and with a resilient sleeve disposed about and covering the outer surface of the cloth. The core member is characterized in that it possesses a specific gravity of less than unity, and has a relatively low bending modulus. The cloth is characterized in that it has a predominance of longitudinally disposed fibers so as to substantially increase the modulus of the structure while only a minimum increase in wall thickness and overall diameter is obtained.

United States Patent 1 Christenson Jan. 21, 1975 REINFORCED TOW HANDLE [75] Inventor: Harlan B. Christensen, Spirit Lake,

[58] Field of Search 114/235 WS; 115/61, 70; 9/310 R; 16/110 R, 111, 116; 161/176 [56] References Cited UNITED STATES PATENTS 3,092,068 6/1963 Brownson 1l5/6.1 3,156,943 11/1964 Groomer et a1. ll5/6.1 3,196,825 7/1965 Spurlock 115/61 3,537,418 1l/1970 Brownson 1l5/6.1

Assistant ExaminerStuart M. Goldstein [57] ABSTRACT An improved gripping handle for a tow line which includes an elongated, generally rigid core member having a layer of glass cloth disposed about and bonded to the outer surface of the core, and with a resilient sleeve disposed about and covering the outer surface of the cloth. The core member is characterized in that it possesses a specific gravity of less than unity, and has a relatively low bending modulus. The cloth is characterized in that it has a predominance of longitudinally disposed fibers so as to substantially increase the modulus of the structure while only a minimum increase in wall thickness and overall diameter is obtained.

10 Claims, 4 Drawing Figures REINFORCED TOW HANDLE BACKGROUND OF THE INVENTION The present invention relates generally to gripping handles for tow lines, and more specifically to an improved gripping handle for a tow line employing a generally rigid core, with the modulus of the structure being improved by utilization of a glass cloth wrap about the core, wherein the wrap has a predominance of longitudinally disposed fibers. The surface of the wrapped core is covered with a sleeve of foamed resilient cellular or smooth coating, such as, for example, frothed polyurethane or the like.

The improved gripping handle means of the present invention provides a finished product which possesses an improved modulus without a significant increase in the diameter of the product. In other words, the modulus of the handle is increased without requiring that the diameter or weight be significantly increased. The finished product is both buoyant and durable, and possesses these characteristics without having a diameter sufficiently large so that it becomes uncomfortable to the user.

The gripping handle devices of the present invention are particularly adapted for use as handles for water ski tow lines. As such, these handles must be buoyant, and at the same time possess a modulus which will provide the required strength and durability. The shock loading imposed upon the handle at the time the skier starts his forward movement and is emerging from the water, and before his skis commence planing is substantial, and those cores with specific gravity of less than unity normally have a low modulus and therefore are not sufficiently durable. The aspect of the present invention permits use of conventional cores such as wood, but the glass cloth wrap enhances the durability significantly.

SUMMARY OF THE INVENTION In accordance with the preferred modification of the present invention, a gripping handle means for a tow line is provided which comprises an elongated generally rigid core member having a layer of glass cloth dis posed firmly and tightly about the outer surface thereof. The glass cloth is preferably bonded to this outer surface so as to be tightly adherent thereto. A resilient sleeve is disposed about and covers the outer surface of the wrapped core. The glass cloth is particularly characterized in that it has a predominance of Iongitudinally disposed fibers which extend generally parallel to the axis of the core. Preferably, the longitudinal fibers comprise more than 60 percent of the weave, and may comprise up to 99 percent of the weave. The transverse fibers are preferably utilized to assist in the holding or retention of the longitudinal fibers in a taut manner about the surface of the core.

The outer surface is preferably a foamed resilient coating, having a closed cell structure. Frothed or foamed polyurethane having a specific gravity of between about 0.5 and 0.8 is preferred. Such a range of specific gravity provides a covering which is durable, and also one which contributes to the buoyancy of the overall composite product. The closed cell structure is also desired from the standpoint of compatability for use with water, particularly wherein the handle may be exposed or immersed in water for substantial periods of time.

Therefore, it is a primary object of the present invention to provide an improved gripping handle for a tow line which employs a generally rigid core member having its modulus improved by the bonding of a layer of glass cloth over the surface of the core, and wherein the glass cloth layer has a predominance of longitudinally disposed fibers.

It is yet a further object of the present invention to provide an improved high strength gripping handle means for a tow line which is both buoyant and durable, and which employs a generally rigid core with a specific gravity of less than unity and having a glass cloth securely bonded to the surface of the core. and further having a sleeve of foamed resilient plastic material formed over the glass cloth layer.

It is still a further object of the present invention to provide an improved high strength buoyant gripping handle means for a tow line which utilizes a generally rigid core provided with a layer of glass cloth disposed about and bonded to the outer surface of the core, and wherein the modulus of the core is enhanced by virtue of the predominance of longitudinally disposed fibers present in the glass cloth wrap.

Other and further objects of the present invention will become apparent to those skilled in the art upon a study of the following specification, appended claims, and accompanying drawing.

BRIEF DESCRIPTION OF THE DRAWING FIG. 1 is a perspective view of the improved gripping handle means of the present invention and illustrating such a structure with a wooden core and also illustrating a segment of the tow line which is coupled to the gripping handle means;

FIG. 2 is a detailed perspective view showing one end segment of the gripping handle means shown in FIG. 1, with the remainder being broken away and with portions of the outer sleeve member and glass cloth wrap being cutaway so as to illustrate the arrangement of the superimposed layers;

FIG. 3 is a sectional view taken through the diameter of the device of FIG. 1 and illustrating the arrangement of the various components in superimposed relationship, one to another; and

FIG. 4 is a sectional view taken along the line and in the direction of arrows 4-4 of FIG. 3, with this view being taken generally across the diameter of the device.

DESCRIPTION OF THE PREFERRED EMBODIMENT In accordance with the preferred modification of the present invention, the gripping handle means generally designated 10 comprises an elongated generally rigid core 11 having a layer of glass cloth 12 disposed about the outer surface thereof. In the embodiment illustrated, the core member 11 is a wooden core member, it being understood that other materials have certain parameters to be described hereinafter may be found useful. Glass cloth layer 12 is bonded firmly to the outer surface of core member 11 so as to be closely adherent to the core member. The resilient sleeve 13 is disposed about the outer surface of the glass cloth and envelopes the glass wrapped core. As is apparent in the view of FIG. 1, rope member segments 14 and 15 are attached to handle means 10 through bores 16 and 17 formed in the core member 11. As is conventional, rope segments 14 and 15 are knotted at the ends in order to provide firm attachment to handle means 10.

Wooden core member 11 may be fabricated from a durable type of wood such as ash, birch, hickory, or oak. Such hardwoods are readily available and provide the required durability for the composite product. As has been indicated, however, other core materials may be found useful in connection with the preparation of products pursuant to the present invention.

As has been indicated, the core material possesses a specific gravity of less than unity. It has been found, however, that most materials of construction having a specific gravity of less than unity also have a relatively low bending modulus. It has been found that the bending modulus may be substantially improved by bonding a layer of glass cloth to the outer surface of the core, it being preferred, however, that the glass cloth have a predominance of longitudinally disposed fibers. This glass cloth, tightly wound about the surface of the core, contributes a significant increase in strength, without adversely increasing the diameter or density of the composite product.

In addition to wooden cores, shafts prepared from extruded or molded synthetic resin foam materials could be employed. Examples of such synthetic resin materials are nylon, ABS, and epoxy resins. Phenolic resins may also be employed for this purpose. Reinforcing materials may also be employed in the core structure per se. Another example of a core material is a thin wall metallic tubing plugged at each end thereof to preserve buoyancy, and thereafter provided with the glass wrap to enhance the bending modulus.

The glass cloth layer 12 has a predominance of longitudinally disposed fibers. The longitudinally disposed fibers preferably comprise at least 60 percent of the material, and may be preferably between 65-80 percent of the composite weave. Such materials are, of course, commercially available. It has been found that the modulus of a wooden core, which traditionally is in the area of about 1,200, is increased substantially by the application of the predominantly longitudinal fibers to the surface. The glass cloth material is preferably impregnated with a resin, such as a polyester, epoxy or other compatible resin, which may be employed to firmly bond the cloth to the core surface. Resin impregnated glass cloth is, of course, commercially available.

The transverse fibers may be utilized for the purpose of increasing the compressional forces which are applied to the fibers in the remaining portions of the weave. As an alternative or added feature, a cellophane wrap may be employed to apply compressional forces against the fibers during cure of the adhesive so as to retain them in place on the surface of the wooden core.

FIG. 2 illustrates the nature of the structure, with the predominance of fibers being illustrated and shown extending in the longitudinal direction. Also, it will be appreciated that either woven or non-woven glass cloth may be employed for this structure of the gripping handle. When non-woven cloth is employed, it may be preferable to wrap the material in cellophane prior to curing the resin which impregnates the cloth. Either thermally or catalytically cured resin may be employed for the purpose of bonding the glass to the core surface, with these adhesives being, of course, commercially available.

Preferably, when a glass cloth having a thickness of about mils is employed for the wrap, approximately six wraps of the cloth will be employed to provide a glass layer thickness of apsioximately 30 mils. Such an arrangement will be sufficient to significantly enhance the modulus of the overall finished product. Also, it will be appreciated that the cloth is firmly held in compression against the surface so as to provide a dense fiber coating or layer.

The foamed coating 13 is preferably foamed polyure thane, but may, alternatively, be frothed polypropylene or frothed polyethylene. In certain instances, other materials such as vinyl or the like may be employed, it being important that the frothed material be of the closed cell type. A smooth sleeve may also be employed. if desired, provided that the overall density of the composite product does not become increased so as to cause the product to lose buoyancy.

A foamed sleeve of polyurethane having a wall thickness of approximately Vs inch, with a specific gravity of about 0.8 has been found useful. The durability of such a product is also adequate for the purposes. Frothed vinyls or polyolefins such as polypropylene or polyethylene having densities in the range of about 0.6 to 0.8 may be employed with benefactory results.

I claim:

1. Gripping handle means for a tow line and comprismg:

a. an elongated generally rigid solid core member with a specific gravity of less than unity and with a relatively low bending modulus, said core member having a centrally disposed axis;

b. a single layer of glass cloth disposed about said core and bonded to the outer surface thereof, and a resilient sleeve disposed about and covering the outer surface of said glass cloth;

c. said glass cloth layer having a predominance of longitudinally disposed fibers extending generally parallel to said core axis; and

d. said composite gripping handle means having a specific gravity of less than unity.

2. The gripping handle means as definedin claim 1 being particularly characterized in that said resilient sleeve is bonded to the outer surface of said glass cloth.

3. The gripping handle means as defined in claim 1 being particularly characterized in that said glass cloth is impregnated with a curable synthetic resin.

4. The gripping handle means as defined in claim 1 being particularly characterized in that said longitudinally disposed fibers comprise at least 60 percent of the total fibers in said layer of glass cloth.

5. The gripping handle means as defined in claim 4 being particularly characterized in that said glass cloth fibers are disposed in a dense spirally arranged wrap extending about said elongated core to a thickness of between about 25 mils and 40 mils.

6. The gripping handle means as defined in claim 1 being particularly characterized in that the wall thickness of said glass cloth comprises between about 6 percent and 8 percent of said core diameter.

7. The gripping handle means as defined in claim 1 being particularly characterized in that said glass cloth includes longitudinal and transverse fibers, and wherein said transverse fibers are wrapped about the surface of said core under tension.

8. The gripping handle means as defined in claim 1 being particularly characterized in that said rigid core member is a wooden shaft.

9. The gripping handle means as defined in claim 8 being particularly characterized in that said glass cloth layer is bonded to the surface of said core with a curable synthetic resin, and wherein said resin is cured while the fibers of said glass cloth are held in compression against the surface of said core.

10. The method of increasing the bending modulus of the wooden core member of a gripping handle for a tow line which comprises:

a. wrapping a layer of glass cloth about the outer surface of said wooden core, said glass cloth having a predominance of longitudinally disposed fibers extending generally parallel to the core axis;

b. bonding said glass cloth layer to the outer surface of said wooden core member while said glass cloth fibers are held in compression about the surface of said wooden core; and

c. enveloping said cloth wrapped wooden core within a sleeve member consisting of a hollow tubular member of a frothed synthetic resin selected from the group consisting of polyethylene, polypropylene, and polyurethane. 

1. Gripping handle means for a tow line and comprising: a. an elongated generally rigid solid core member with a specific gravity of less than unity and with a relatively low bending modulus, said core member having a centrally disposed axis; b. a single layer of glass cloth disposed about said core and bonded to the outer surface thereof, and a resilient sleeve disposed about and covering the outer surface of said glass cloth; c. said glass cloth layer having a predominance of longitudinally disposed fibers extending generally parallel to said core axis; and d. said composite gripping handle means having a specific gravity of less than unity.
 2. The gripping handle means as defined in claim 1 being particularly characterized in that said resilient sleeve is bonded to the outer surface of said glass cloth.
 3. The gripping handle means as defined in claim 1 being particularly characterized in that said glass cloth is impregnated with a curable synthetic resin.
 4. The gripping handle means as defined in claim 1 being particularly characterized in that said longitudinally disposed fibers comprise at least 60 percent of the total fibers in said layer of glass cloth.
 5. The gripping handle means as defined in claim 4 being particularly characterized in that said glass cloth fibers are disposed in a dense spirally arranged wrap extending about said elongated core to a thickness of between about 25 mils and 40 mils.
 6. The gripping handle means as defined in claim 1 being particularly characterized in that the wall thickness of said glass cloth comprises between about 6 percent and 8 percent of said core diameter.
 7. The gripping handle means as defined in claim 1 being particularly characterized in that said glass cloth includes longitudinal and transverse fibers, and wherein said transverse fibers are wrapped about the surface of said core under tension.
 8. The gripping handle means as defined in claim 1 being particularly characterized in that said rigid core member is a wooden shaft.
 9. The gripping handle means as defined in claim 8 being particularly characterized in that said glass cloth layer is bonded to the surface of said core with a curable synthetic resin, and wherein said resin is cured while the fibers of said glass cloth are held in compression against the surface of said core.
 10. The method of increasing the bending modulus of the wooden core member of a gripping handle for a tow line which comprises: a. wrapping a layer of glass cloth about the outer surface of said wooden core, said glass cloth having a predominance of longitudinally disposed fibers extending generally parallel to the core axis; b. bonding said glass cloth layer to the outer surface of said wooden core member while said glass cloth fibers are held in compression about the surface of said wooden core; and c. enveloping said cloth wrapped wooden core within a sleeve member consisting of a hollow tubular member of a frothed synthetic resin selected from the group consisting of polyethylene, polypropylene, and polyurethane. 